Sanitary appliances such as sanitary napkins, diapers and wound dressings are all made of similar construction. All of the sanitary appliances have a fluid permeable cover, an absorbent matrix and a fluid impermeable baffle. The fluid permeable cover is, of course, located adjacent the discharge orifice and is designed to rapidly pass fluid through itself and into the absorbent matrix. Occasionally, during periods of heavy discharge, particularly in the case of relatively viscous discharge fluids such as menses, the fluid may run off the surface of the cover material or wick along the various interstices rather than migrating downward into the absorbent.
This problem has been recognized and dealt with by utilizing one of the properties of the wrap. The wrap used in sanitary napkins and wound dressings, as well as diapers and incontinence pads, is traditionally a nonwoven synthetic material. The baffle utilized in these sanitary appliances is conventionally a thermoplastic sheet.
One of the approaches utilized to prevent fluid runoff is disclosed in U.S. Pat. Nos. 3,294,091 and 4,200,103 in which the thermoplastic baffle is positioned not only on the bottom of the appliance, but also along the sides and covers the longitudinal top edges. The baffle is then fused to the wrap to provide a fluid migration barrier. Fusing has also been used to seal a napkin at its edges. An example of such a napkin is disclosed in U.S. Pat. No. 4,059,114. It is also known to emboss sanitary napkins and particularly the thin napkins of the panty shield type to provide integrity to the batt of absorbent material. An example of such a napkin is disclosed in U.S. Pat. No. 3,881,490.
Prior art utilization of fusing fluid pervious wraps to fluid impervious baffles at the top portion of the napkin as described in U.S. Pat. No. 3,294,091 involves precise positioning of the fusing element and must be done after assembly of the napkin. As such, it is much more difficult to properly position all of the elements to create a uniform barrier line. Also, this approach tends to damage the absorbent capacity of the absorbent layer underneath due to the application of heat necessary for fusing. Positioning of the barrier is also dependent upon precise positioning of the baffle and the location of the barrier is also predetermined by the variety of possibilities of baffle configuration and position.